Modules/MTA-MySQL/mysql fetch field

	This function is provided by the external module MTA-MySQL. You must install this module to use this function.

Returns a table with information about a field in a query result. You can call repeatedly this function to return all the result fields, and when it reaches the end returns nil. You can also go to a specific field using mysql_field_seek().

Syntax

table mysql_fetch_field ( MySQLResult result )

Required arguments

• result: A valid MySQL result

Returns

A table with information about a field with the following keys:

• name: The name of this field.
• org_name: If you used aliases in the query, the original name of the field.
• table: The table of this field.
• org_table: If you used aliases for the table, the original name of the table.
• length: The maximum length allowed by this field in the table definition.
• max_length: The maximum length of this field in all the result rows.
• not_null: True if the field can't be NULL (See mysql_null()).
• primary_key: True if the field is the table primary key.
• unique_key: True if the field value is unique.
• multiple_key: True if the field is part of a key.
• numeric: True if the field is numeric.
• blob: True if the field is a BLOB.
• unsigned: True if the field is unsigned.
• zerofill: True if the field is zero filled.
• type: A string representing the type of this field.

Example

Example 1: This example shows how to print the rows of a result set showing the field name.

local result = mysql_query(handler, "SELECT * FROM account") -- Execute the query
for result,row in mysql_rows(result) do -- Iterate through all the result rows
  mysql_field_seek(result, 1) -- Reset the field cursor to the first field
  for k,v in ipairs(row) do
    local field = mysql_fetch_field(result) -- Retreive the field data
    if (v ~= mysql_null()) then
      outputDebugString("row[" .. field["name"] .. "] = " .. v)
    else
      outputDebugString("row[" .. field["name"] .. "] = NULL")
    end
  end
end
mysql_free_result(result) -- Free the result

See also

• mysql_data_seek
• mysql_fetch_field
• mysql_fields
• mysql_fetch_lengths
• mysql_fetch_row
• mysql_rows
• mysql_fetch_assoc
• mysql_rows_assoc
• mysql_field_length
• mysql_field_name
• mysql_field_seek
• mysql_field_tell
• mysql_num_fields
• mysql_num_rows
• mysql_result
• mysql_free_result
• mysql_null